Scope: This Guideline provides a method for determining when meter curves are
required to be generated and the conditions for acceptance.
Frequency: As indicated below
Procedure This check is intended to verify that the meter K-Factor calculations are
performed within acceptable levels of uncertainty. Proof run printouts will
be the source of the factors used in the K-Factor equation.
PREPARATIONS:
This task must be undertaken when crude oil / product is flowing through
the metering stream. However, ensure that this task does not interfere
with the normal operation of the prover. Give a brief description of the test
in the Metering Log Book.
Record the results of this test on the “K” Factor Computation Test Sheet,
attached.
K-FACTOR CALCULATION AND COMPUTATION CHECK PROCEDURE:
The prover computer calculated K-Factor should be confirmed using the
following procedure: –
a) Prior to carrying out this test, examine all drain and vent valves to
ensure that there is no leakage from the system.
b) Request a stream to be proved and check the integrity of the
relevant stream isolation valve and prover alignment valves once
the prove sequence is initiated.
c) On completion of the proof sequence the calculations will be
checked. The meter K-Factor is calculated using the following
formula:
K = n x Ctlm x Cplm / Vb x Ctlp x Cplp x Ctsp x Cpsp
Where:
N = Number of pulses accumulated during proving run
between operations of detector switch 1 to switch 2
and switch 2 to switch 1.
Ctlm =
The temperature correction factor for the liquid at the
meter.
Cplm =
The pressure correction factor for the liquid at the
meter.
Vb =
The base volume of the prover.
Ctlp =
The temperature correction factor for the liquid at the
prover.
Cplp = The pressure correction factor for the liquid at the
prover.
Cpsp =
The pressure correction factor for steel at the prover.
Ctsp =
The temperature correction factor for steel at the
prover.
d) Complete the K-Factor Calculation Test Sheet using data from the
proof-run printout. If the calculated and actual K-Factors are within
tolerance the check is complete.
e) If the calculated and printed K-Factors are out of tolerance
investigate the reason and attempt corrective action. If a significant
error is still observed, change the flow computer.
f) Once the calculated and actual K-Factors are within tolerance
complete the test sheet and ensure it is marked with appropriate
comments. The test is complete.
g) Enter details of all tests in the Metering Log Book.
K-FACTOR COMPUTATION TEST SHEET
